6.4.3: An upcoming maintenance release

WordPress 6.4.3 is scheduled to be the next maintenance release for the 6.4 version. Its release will follow the following preliminary schedule:

  • 25 January 2024 – Release Candidaterelease candidate One of the final stages in the version release cycle, this version signals the potential to be a final release to the public. Also see alpha (beta). made available and announced here on the make/coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. site.
  • 30 January 2024 – Final release made available.

Specific times will be decided in advance and adjustments to the schedule may be made. All adjustments will be noted in this post.

Minor or Maintenance releases of WordPress are intended as bugbug A bug is an error or unexpected result. Performance improvements, code optimization, and are considered enhancements, not defects. After feature freeze, only bugs are dealt with, with regressions (adverse changes from the previous version) being the highest priority.-fix releases. Currently, four bug fixes have been merged into the 6.4 branchbranch A directory in Subversion. WordPress uses branches to store the latest development code for each major release (3.9, 4.0, etc.). Branches are then updated with code for any minor releases of that branch. Sometimes, a major version of WordPress and its minor versions are collectively referred to as a "branch", such as "the 4.0 branch". with seven additional tickets intended for this release. If you have a ticketticket Created for both bug reports and feature development on the bug tracker. that you think should be considered, please put it in the milestone or if you lack bug gardening capabilities, add a comment here. Note: except in extreme situations, only bug fixes will be considered and generally only bugs that have been introduced during the 6.4 cycle.

Final note: Some default themes are also receiving updates, but these will be happening separately even though the tickets are in the 6.4.3 milestone. See #60267 for more information. Update: The theme updates have been released

Get involved with 6.4.3

Bug Scrubs will happen in the #core room during the follow times:

Each of the open tickets is going to require development work along with testing and review. You can also run scrubs to help ensure that the correct tickets all are fixed in this release. Additionally, while the intent is for no new strings in this release, some locales have strings in 6.4 in need of translation.

General coordination for the release will happen in the #6-4-release-leads channel and decisions around code for the release will be made in the #core room.

This minor releaseMinor Release A set of releases or versions having the same minor version number may be collectively referred to as .x , for example version 5.2.x to refer to versions 5.2, 5.2.1, 5.2.3, and all other versions in the 5.2 (five dot two) branch of that software. Minor Releases often make improvements to existing features and functionality. will be led by @mikachan, @joemcgill, and myself (@jorbin).

Thank you to @fabiankaegy, @annezazu, @hellofromtonya for pre-publication review.

#6-4, #maintenance

WordPress 6.4.1 Rapid Maintenance Release: Technical Details and Timeline

On November 7, 2023, WordPress 6.4 was released. 🎉 Every release is a massive undertaking that requires the time and hard work of hundreds of contributors often spanning three to four months. Even though WordPress strives to ship excellent, bugbug A bug is an error or unexpected result. Performance improvements, code optimization, and are considered enhancements, not defects. After feature freeze, only bugs are dealt with, with regressions (adverse changes from the previous version) being the highest priority.-free code, technology is fast-moving and edge cases can sometimes make it past testing.

After the 6.4 release, it was reported that a small change within the bundled library responsible for making and managing HTTPHTTP HTTP is an acronym for Hyper Text Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. requests was causing problems for a small subset of sites. The bug was mainly surfacing in the form of failed pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party and theme updates where the attempt would take a long time to process and ultimately result in a timeout error. However, custom code using the HTTP APIAPI An API or Application Programming Interface is a software intermediary that allows programs to interact with each other and share data in limited, clearly defined ways. to make requests was also affected.

After an in-depth investigation, the conditions required were finally identified and understood. To reproduce the problem, a server had to be running a version of curl between 7.22.0 and 7.46.0 while also using HTTP1 and `Keep-Alive`. In curl 7.47.0, a change was made to always prefer HTTP/2 when available. HTTP/1.1 requests default to keeping a connection open, but HTTP/2 prohibits connection-specific header fields including `Keep-Alive` and `Connection`. In this scenario, no `Connection: close` headerHeader The header of your site is typically the first thing people will experience. The masthead or header art located across the top of your page is part of the look and feel of your website. It can influence a visitor’s opinion about your content and you/ your organization’s brand. It may also look different on different screen sizes. was being sent when these conditions were met, so connections remained open until reaching the time out duration and returned an error.


Below is a timeline of relevant events (all times are in Coordinated Universal Time or UTC):

November 7, 2023:

November 8, 2023:

November 9, 2023:


At the time of publishing, approximately 93% of all sites running the 6.4 major version have updated to the 6.4.1 release, with more updating every minute.

To safeguard against future related issues, contributors are exploring ways to better test against different versions of curl. It is always strongly recommended to run current and supported versions of all software. This recommendation is not just for PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher and WordPress itself, but also for command line tools such as curl. As a project, we remain staunchly committed to backwards compatibility, but this is a safety net, not a substitute for that recommendation.

There are many moving parts that make individual WordPress releases increasingly challenging. Preparing, testing, and confidently releasing a version of software that powers over 43% of the web in under 24 hours is an exceptional accomplishment. It would not have happened without the 45+ contributors across the globe who dropped what they were working on to collaborate on solving this problem for site owners everywhere.

Props @chanthaboune, @cbringmann, @jeffpaul, @barry for pre-publish review.